This invention relates to a method and apparatus for processing and removing impurities from an industrial air stream utilized to sterilize medical equipment.
In the prior art, various processes have been developed to sterilize medical equipment between each use. One known method includes placing the instruments within a sealed plastic package. The bag has pore sizes that are too small for airborne impurities to enter through the plastic. The bag is placed in a sealed container, and the atmosphere is driven out of the container and replaced with a sterilizing chemical which has the ability to permeate the small pores in the plastic. This sterilizing chemical sterilizes the instrument. The sterilizing chemical is then evacuated from the chamber, and the chamber is then exposed to atmosphere. The instrument will remain sterile until the bag is opened to use the instrument.
These type processes have been very successful in efficiently and effectively sterilizing medical equipment. However, strict regulations require that the sterilizing chemical, typically ethylene oxide, be removed from the industrial air stream before it is returned to atmosphere. In particular, at least 99% of this material must be removed before the industrial air stream can be returned to atmosphere.
It has been the desire of the industry to have the ethylene oxide combusted. In this way, the components of the ethylene oxide are broken down into basic chemical components of carbon dioxide and water. However, ethylene oxide is very volatile. When the ethylene oxide is mixed with even a small amount of oxygen, it can become explosive. Standard oxidizers expose the ethylene oxide to oxygen before the ethylene oxide is directed into a combustion chamber. Thus, prior attempts to combust ethylene oxide are extremely dangerous, and several systems have actually exploded.
The situation has become so grave that regulators have considered reducing the requirement of removing the ethylene oxide, as there has been no safe method proposed to remove the ethylene oxide from the air stream.
In standard chemical manufacturing processes, it has been proposed to remove chemical byproducts and direct them into the combustion chamber of a thermal oxidizer without allowing access to oxygen. These systems have never been proposed for handling ethylene oxide, nor have they been proposed for sterilization systems, or even systems generally in the medical field.